The present invention concerns an apparatus for optical scanning of multiple specimens, the specimens being associated with a specimen receiving device and being optically scannable by a scanning device. In addition to that the invention concerns as well with an apparatus for scanning multiple specimen regions on a large specimen.
Arrangements of the generic type are used in particular for the detection of “micro-array biochips” (MABs). MABs are used in medical diagnostics, where a large number of MABs need to be examined and evaluated in a brief period of time. Specimen holders on which a large number of specific detection regions (“spots”) are placed, preferably in a grid pattern, are among the devices that can be used as MABs. These detection regions usually have a diameter of approximately 50 to 100 μm and need to be examined in terms of their fluorescence properties. The spots are distributed on a specimen holder over a specimen field of up to 22×60 mm.
Specimens distributed over such large object fields cannot be simultaneously imaged with a conventional confocal laser scanning microscope (CLSM), however, since the object fields of microscope objectives suitable for such applications are too small for the purpose. The use of larger objectives or lenses, with a beam that is moved relative to the lenses, results in image irregularities and intensity fluctuations. The image irregularities are caused by residual or imaging errors in the lenses used, and the intensity fluctuations by partial contamination of the optical components in the beam path.
In addition, the illumination beam path of CLSMs is configured in such a way that the diffraction-limited scanning beam generally has, a diameter in the specimen plane in the range of 1-2 μm. As a result, the specimens are scanned with a spatial resolution that is unnecessary and much too high for these applications. Laboratory use, in particular, demands a high throughput of specimen holders for examination, which is not attainable with presently known CLSMs. The operation of CLSMs is moreover complex, and requires considerable operating experience on the part of the user.